The Biostatistics and Data Management Core (BDMC) will provide data entry, data management, computer systems and analytical support to the Multipurpose Arthritis Center and Musculoskeletal Diseases Center (MAC). The BDMC will create new databases for MAC projects, current and proposed, with appropriate linkage to existing databases. New databases will be created with the assistance of this Core designing data collection instruments, training data collection personnel, computerizing data, and developing and performing quality control functions. Systems will be developed to enable data to be electronically transmitted to the Core since data for projects will be collected at distant sites throughout the nation. For data collected locally, the BDMC will enter data for new databases, and support data entry for the existing arthritis, Rheumatism, and Aging Medical Information System (ARAMIS) databases. Data management and systems support will be provided to Research Base investigators. The BDMC will provide support for analyzing and presenting data collected under the auspices of the MAC. This core will also assist with study design for proposed new projects by Research Base investigators.